1. Field of the Invention
The present invention relates to a cutter body and a rotary tool for use in milling, as well as a method for assembling the rotary tool.
2. Description of the Related Art
Cutters and end mills having a plurality of cutting edges are conventionally known. In these tools, when cutting inserts are mounted, the cutting edge height may vary among the mounted cutting inserts. This is because the cutting edge height varies depending on the fabrication accuracy of cutters and cutting inserts. When a tool is applied to cutting while the cutting inserts differ in cutting edge height, satisfactory surface roughness may fail to be obtained, or the life of the tool may be shortened. Particularly, in the case of cutting inserts each having a diamond cutting edge, an irregular cutting edge height causes concentration of load on a particular cutting insert. As a result, the life of that cutting insert is highly likely to be shortened because of low toughness. In many cases, a rotary tool for cutting an aluminum workpiece is rotated at high speed and is thus highly susceptible to an irregular cutting edge height among cutting inserts.
In order to reduce surface roughness (e.g., Rz), a conventionally used milling cutter or end mill allows the position of a cartridge to be adjusted in the height direction. FIG. 12 shows an example of such an adjustment mechanism. An adjustment screw 60 is provided substantially perpendicular to the direction of adjustment. Movement of the adjustment screw 60 is transmitted to a taper portion 62 of a cartridge 61 so as to move the cartridge 61 in the direction of adjustment, thereby adjusting the cutting edge height (see Japanese Patent Application Laid-Open (kokai) No. 200-15503). In FIG. 12, reference numeral 63 denotes a cutter body; reference numeral 64 denotes a cartridge fixation screw for fixing the cartridge 61 to the cutter body 63; reference numeral 65 denotes a cutting insert; reference numeral 66 denotes an insert attachment screw for fixing the cutting insert 65 to the cartridge 61; and reference numeral 67 denotes an L-shaped wrench, which is inserted into a wrench reception socket 68 of the adjustment screw 60 and rotated.
In the thus-configured rotary tool, once the cartridges 61 undergo positional adjustment, after the cutting insert 65 is replaced, no further positional adjustment is necessary for the cartridges 61, since the cutting inserts 65 have excellent dimensional accuracy. Thus, the tool can be used while a regular cutting edge height is maintained.
3. Problems to be Solved by the Invention
However, when the adjustment screw 60 or the cartridge fixation screw 64 in an adjustment mechanism section is mistakenly moved, established adjustment is disturbed, potentially resulting in a need to readjust by use of a highly accurate apparatus.